Adult mesenchymal stem cells (MSCs) are capable of robust tissue repair. MSCs can be isolated from many autologous tissue sources with the two most common sources being adipose tissue and bone marrow. Adipose stem cell harvesting is performed through liposuction of subcutaneous fat tissue which is then usually processed with a chemical digestion technique. Bone marrow aspirate is a red liquid when first obtained from the patient through a trocar inserted through the bony cortex. The aspirate fluid is then typically processed with centrifugation to separate out various marrow fractions (referred to herein as fractions or layers). The buffy coat is a middle fraction of centrifuged marrow, positioned below a serum component and above a red blood cell component. The buffy coat is rich in nucleated cells, progenitor cells, and stem cells.
Until recently, only the buffy coat of a fractionated bone marrow aspirate was known to include useful quantities of MSCs. Accordingly, typical bone marrow fractionation and concentration systems designed to isolate a therapeutically significant quantity of MSCs have focused on isolating and processing the buffy coat through various means. Conventional methods and devices do not provide for the isolation or subsequent processing of other marrow fractions that are now known to contain MSCs, in particular a marrow adipose layer supernatant which is positioned above the serum layer when bone marrow aspirate is fractionated. Therefore, according to conventional techniques, the marrow adipose supernatant layer is discarded as waste.
Although the adipose layer supernatant of fractionated bone marrow aspirate is now known to include MSCs, no techniques are known for efficiently collecting the adipose layer supernatant and processing same to maximize a useable MSC yield.
The embodiments disclosed herein are directed toward overcoming one or more of the problems discussed above.